One disadvantage I see with your plan to learn Spanish - if I may say so - is that you don't want to learn to read or write it, just learn to speak it. This may work out to your detriment, so I would recommend taking a Spanish class at your local community college or university, and learning the language thoroughly. Why?
Because you have to communicate with mostly Spanish-speaking parents. And the way that happens about 75% of the time at school is through notes sent home. Spanish-speaking parents usually can't read notes sent home in English, and that's unfair to them.
I don't know if your district has translators who would do this kind of job - my mom is a bilingual teacher's aide in a district where 90% of the parents also do not speak English - the predominant other language used to be Spanish, but now, the predominant other languages are Spanish, Farsi and several Indian dialects. District-employed translators are the ones who have the job of translating notes and other communications going home to the parents. My mom used to be the only Spanish translator for the district, but she has since given it up because the district hired more people to do the job and then did not offer to keep her on the translation team, although they still freely use the majority of her templates and documents and materials she developed, without ever asking her permission. I'm not sure if her permission was absolutely necessary, but they should have done so as a courtesy to her, because she had to make up many of these forms in Spanish out of whole cloth; they were not available from the state, the district or any other source.
I would find out if this is available, and if not, ask any available Spanish-speaking staff if they would mind helping you out in translating notes for parents. Please keep in mind that this is no minor task and they may have to obtain special permission from the school district, because the district or the union may have special rules or bylaws regarding how these kinds of duties are carried out, how they are paid, etc.
I do speak, read and write Spanish fluently, so if you ever need help on words/phrases, pronunciation basics, etc, I'd be more than happy to help you.
¡Buena suerte, y que le vaya bien! (good luck, and I hope it goes well!)